Thanks for signing up! You might also like these other newsletters:

Q1. I am a diabetic and have smoked for many years, but want to quit. I read about the anti-smoking drug Chantix and heard people say it really works. I tried it and after a week my smoking decreased, but my blood sugar levels went up. I finally had to stop taking this drug. Is there a reason my levels would go up?

— Suzanne, Tennessee

Congratulations on your desire to stop smoking. As I often say to my patients, it is the most important decision you will make to stay healthy.

Chantix (vareniciline) has been shown to be more effective than other anti-smoking aids, including Zyban (bupropion) and nicotine replacement therapy. And, yes, in the rare individual, Chantix has been associated with increased blood glucose levels. The mechanism for this effect is not known. Chantix also has other side effects of greater concern, namely, depressed mood and suicidal ideation. Therefore, close monitoring is very important if you decide to take this drug.

You should discuss with your doctor the best way to support your decision to stop smoking. I believe that the most effective smoking cessation therapy is a combination of nicotine replacement therapy (for example, patches or gum), medication such as Chantix or Zyban, and psychotherapy. I wish you success.

Q2. I'm trying to stay away from artificial sweeteners. Can I use stevia instead?

— Cheryl, Ohio

Stevia is a no-calorie sweetener extracted from the leaf of a plant grown in Paraguay and Brazil. The ingredients in stevia that make it sweet include the plant chemicals stevioside, rebaudiosides, and dulcoside A. Stevia is about 30 times sweeter than sucrose (table sugar).

The U.S. Food and Drug Administration (FDA) initially approved stevia for use as a food additive in the United States — not as a sweetener — so there was no official acceptable daily intake for this additive. However, based on safety studies in rats, a daily intake of 8 milligrams per kilogram of body weight (4 milligrams per pound of body weight) is considered safe. One packet usually contains 80 mg of stevia. So, you can safely use stevia within this dose limitation.

Rebaudioside A is a specific extract of the stevia plant that is the sweetest (about 350 times sweeter than table sugar) and has the least bitter aftertaste of the components of stevia. In December 2008, the FDA approved several rebaudioside A-based products for sale, including the sweeteners Truvia and Purevia. These products have an acceptable daily intake of up to 4 milligrams per kilogram of body weight.

Q3. I've heard in the news that the diabetes drug that I take — Avandia — can cause heart problems. Is that true, and if so, should I switch to another drug?

Lowering blood glucose can ultimately benefit the heart, and Avandia has been shown to reduce glucose effectively. But recent data from the maker of Avandia reported by the Food and Drug Administration (FDA) shows that Avandia raises LDL and triglycerides compared with Actos (pioglitazone), another drug in the same class. Also, although recently published data from a research study conducted by Avandia's manufacturer did not report an increased risk of heart attack or stroke, these results have been questioned. Therefore, the FDA has recommended that a strong warning be added to the drug labeling regarding its potential effect on the heart, but voted to keep the drug on the market.

What the published data have confirmed beyond dispute, however, is that Avandia increases the risk of fatal or non-fatal heart failure. This is much more relevant for individuals who are already at risk for heart failure due to issues like age, excessive weight, kidney disorder, and high blood pressure.

Another consideration — for women especially — is the effect of Avandia and Actos on bone density. Both have been shown to increase the risk of fractures. For these reasons, Avandia should not be the first drug a doctor prescribes to treat high glucose levels. Sulfonylureas and metformin, for example, also lower blood glucose levels. A doctor might try these drugs before prescribing Avandia.

So should you stop taking Avandia? Given the latest round of studies, it's clear that individuals who are at a significant risk for heart attacks or congestive heart failure should not take this drug. My advice to you, therefore, is to have a conversation with your doctor.